32 research outputs found
Donar acceptor systems based on corroles, porphyrins and NIR Aza-BODIPYS
No full textby Naresh BalsukuriPh.D
Singlet-singlet energy transfer in carbazole-porphyrin dyads and triads
No full textDonor-Acceptor (D-π-A) type carbazole-porphyrin dyads and triads were synthesized in good yields through palladium catalyzed coupling reactions. The length of the spacer between the D (carbazole) and A (porphyrin) was varied from “phenyl-ethyne” to “ethyne linkage”. The effect of the linker length on the spectral properties of these D-π-A dyads and triads was studied. The N-butyl-3-ethynyl-carbazole was coupled with different porphyrins bearing either one or two meso-p-iodophenyl group/meso-bromo groups using palladium catalyst. All the dyads and triads were characterized by MALDI-MS, NMR, UV–vis absorption, fluorescence and cyclic voltammetry techniques. The S1 emission dynamics were analyzed by time-resolved spectroscopy (TCSPC); an efficient energy transfer up to 84% was observed from donor groups to the porphyrin core. Electrochemical studies revealed that, compounds having freebase porphyrin components are difficult to reduce as indicated by the cathodic shift in their reduction potentials. On the contrary, the compounds having zinc porphyrin components are easy to reduce as reflected by the anodic shift in their reduction potentials. The lowest HOMO-LUMO gap was found for the dyad which has short linker between D and A.by Naresh Balsukuri and Iti Gupt
Donor-Acceptor (D-A) type systems based on Porphyrins/Corroles and NIR-azaBODIPYs
No full textby Naresh Balsukuri and Iti Gupt
Carbazole-corrole and carbazole-prophyrin dyads: synthesis, fluorescence and electrochemical studies
No full textDonor–acceptor type carbazole–corrole and carbazole–porphyrin dyads 4–9 were synthesized and characterized. Corrole and porphyrin containing one meso-p-iodophenyl group were coupled to N-butyl-3-ethynyl-carbazole by a modified Sonogashira reaction. All the dyads were characterized by HRMS mass, NMR, UV-vis absorption, fluorescence and electrochemical techniques. Fluorescence studies of dyads 4, 7 and 8 indicated energy transfer from the donor carbazole moiety to the corresponding acceptor corrole/porphyrin moiety (up to 80%). The electron-releasing N-butyl-carbazole group affects the electronic properties of the corrole and porphyrin macrocycles in the dyads 4–9. Electrochemical studies revealed that dyads 4 and 5 are difficult to reduce compared to their corresponding monomers, as reflected by the cathodic shift in their reduction potentials. Meanwhile, dyads 6–9 exhibited an anodic shift in their reduction potentials, suggesting that they are easy to reduce compared to their corresponding monomers.by Iti Gupta, Naresh Balsukuri and Sudipta Da
Donor acceptor type ferrocene substituted AZA-bodipys: synthesis, optical and electrochemical studies
No full textby Naresh Balsukuri, S. Mori and Iti Gupt
Difunctionalized N-Confused porphyrins: synthesis, fluorescence, and electrochemical studies
No full textSeven di-substituted N-confused porphyrins (NCPs) 9–15 bearing two aryl functional groups (cis-A2B2 type) were synthesized in 4–7 % yields via [3+1] approach. The corresponding five 5,10-diaryl-substituted symmetrical tripyrranes 1–5 were prepared and condensed with 2,4-bis(hydroxypentaflurophenyl)pyrrole 6. Two outer N-methyl type A2B2 NCPs 14 and 15 were also prepared via a similar approach using a new key precursor 8. All the porphyrins 9–15 were characterized by high-resolution mass spectrometry, NMR, infrared spectroscopy, UV–visible spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. Fluorescence studies of 9–15 showed blue-shifted emission maxima and lower Stokes shifts values when compared with N-confused tetraphenylporphyrin (NCTPP). Electrochemical studies indicated easier oxidation of N-methyl NCPs 14 and 15 when compared with remaining NCPs 9–13.by Sudipta Das, Naresh Balsukuri, E. Kesavan Praseetha and Iti Gupt
